package com.example.gulimall.cart.interceptor;

import com.example.common.constant.CartConstant;
import com.example.common.constant.RedisConstant;
import com.example.common.vo.MemberResponseVo;
import com.example.gulimall.cart.to.UserInfoTo;
import org.apache.commons.lang3.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.UUID;

/**
 * 购物车拦截器组件
 * 在执行目标方法之前，判断用户的登录状态.并封装传递给controller目标请求
 *
 * @author gulin
 * @date 2021/8/17 10:20
 */
public class CartInterceptor implements HandlerInterceptor {

    //同一个线程共享数据，核心原理就是map
    public static ThreadLocal<UserInfoTo> toThreadLocal = new ThreadLocal<>();


    /**
     * 目标方法执行之前
     *
     * @param request
     * @param response
     * @param handler
     * @return: boolean
     * @author gulin
     * @date 10:39 2021/8/17
     **/
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        UserInfoTo userInfoTo = new UserInfoTo();
        HttpSession session = request.getSession();
        //获取当前登录用户信息
        MemberResponseVo memberResponseVo = (MemberResponseVo) session.getAttribute(RedisConstant.LOGIN_USER);
        if (null != memberResponseVo) {
            //用户登陆了
            userInfoTo.setUserId(memberResponseVo.getId());
        }
        Cookie[] cookies = request.getCookies();
        if (null != cookies && cookies.length > 0) {
            for (Cookie cookie : cookies) {
                //user-key
                String name = cookie.getName();
                if (name.equals(CartConstant.TEMP_USER_COOKIE_NAME)) {
                    userInfoTo.setUserKey(cookie.getValue());
                    //标记已经是临时用户
                    userInfoTo.setTempUser(true);
                }
            }
        }
        //如果没有临时用户则分配一个临时用户
        if (StringUtils.isBlank(userInfoTo.getUserKey())) {
            String uuid = UUID.randomUUID().toString();
            userInfoTo.setUserKey(uuid);
        }
        //目标方法执行之前 存入ThreadLocal
        toThreadLocal.set(userInfoTo);
        return true;
    }

    /**
     * 业务执行之后，分配临时用户来浏览器保存
     *
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        //获取当前用户配置
        UserInfoTo userInfoTo = toThreadLocal.get();
        //如果没有临时用户一定保存一个临时用户
        if (!userInfoTo.getTempUser()) {
            //创建cookie
            Cookie cookie = new Cookie(CartConstant.TEMP_USER_COOKIE_NAME, userInfoTo.getUserKey());
            //扩大作用域
            cookie.setDomain("gulimall.com");
            //设置过期时间
            cookie.setMaxAge(CartConstant.TEMP_USER_COOKIE_TIMEOUT);
            response.addCookie(cookie);
        }
    }
}
